Darktable is an open source application that provides both amateur and enthusiasts photographers with a virtual lighttable and darkroom that allows them to manage their digital negatives in a single and handy database. It has been designed from the ground up to be used for developing RAW images from digital cameras.
Features at a glance

Key features include an astonishing graphical user interface designed for the modern computer user, support for importing single image files, folders, and scan for devices, ability to categorize images by numerous filters, such as ISO, color label, rights, creator, publisher, camera, date, time, title, lens, aperture, etc., as well as to access recently used collections.

In addition, the application lets users to view detailed information about an image, if available, such as lens, exposure, aperture, focal length, focus distance, ISO, model, maker, filmroll, image id, filename, version, full path, width, height, copyright, local copy, date, time, title, creator, latitude, and longitude.

It also features fully non-destructive editing, 4×32-bit floating point pixel buffers, GPU acceleration via OpenCL, built-in ICC profiles (sRGB, XYZ, linear RGB and Adobe RGB), zero-latency fullscreen mode, tethered shooting, flexible search functionality, powerful export system, and many translations.

The program is capable of importing a wide range of standard, RAW and HRD image formats, among which we can mention JPG, CR2, HDR, and PFM, and can export images to Picasa and Flickr, as well as to export to low dynamic range (JPEG, PNG, TIFF), linear high dynamic range (PFM, EXR) and 16-bit (PPM, TIFF) images

What News on Darktable 2.0.3 :

• Bugfixes:
• Actually allow printing with ctrl-p shortcut as advertised in the tooltip
• Fix scrolling of the histogram to change the exposure
• Fix the restricted histogram when color picking an area
• Fix a bug in color reconstruction
• Fix an OpenCL bug in tonecurve
• Fix a small memory leak
• Better error messages in darktable-cli
• Fix params introspection for unsigned types
• Only depend on glib 2.32
• Base Support:
• Fujifilm X70
• Olympus PEN-F
• Panasonic DMC-LX3 (1:1)
• White Balance Presets:
• Canon EOS 1200D
• Canon EOS Kiss X70
• Canon EOS Rebel T5
• Canon EOS 5DS
• Canon EOS 5DS R
• Canon EOS 750D
• Canon EOS Kiss X8i
• Canon EOS Rebel T6i
• Canon EOS 760D
• Canon EOS 8000D
• Canon EOS Rebel T6s
• Fujifilm X-Pro2
• Fujifilm X20
• Fujifilm X70
• Olympus PEN-F
• Noise Profiles:
• Canon EOS 5DS R
• Fujifilm X20
• Olympus E-PL6
• Translation updates:
• Danish
• German
• Swedish

Install Darktable 2.0.3 on Ubuntu and Linux Mint Derivative System

Because it is available via PPA, installing Darktable 2.0.3 on Ubuntu 16.04 Xenial Xerus, Ubuntu 15.10 Wily Werewolf, Ubuntu 15.04, Ubuntu 14.10 and derivative systems is easy. All you have to do is add the ppa to your system, update the local repository index and install the darktable package. Like this:

sudo add-apt-repository ppa:pmjdebruijn/darktable-release

sudo apt-get update

sudo apt-get install darktable

to remove, do :

sudo apt-get remove darktable

For other linux distribution you can follow this page

The source is available now. Binary packages are in the process of being built, and will appear soon at their respective download locations.